Magnetics Business & Technology - September/October 2023 - 23

RESEARCH & DEVELOPMENT
weight of 74 kilograms, the EVSys800, normalized to the same
output as the latest ZF 800-volt series drive, is about 40 kilograms
or 30% lighter, contributing significantly to the weight savings of
the vehicle.
Essential for this is the electric motor with a new cooling concept
and the new winding technology. For cooling, ZF allows oil to flow
directly around the copper rods exactly at the point where most
heat is generated during operation. Such highly efficient cooling
significantly increases performance with the same weight and
installation space. In addition, the use of heavy rare earths can be
dispensed with. The braided winding technology developed and
patented by ZF, is a further development of the so-called wave
winding and enables a total of 10% less installation space. The
winding head alone is up to 50% smaller than with conventional
approaches, saving about 10% copper.
As a result of the overall thermal management, the range of the
EVbeat increases by up to a third in demanding winter operation.
The significantly better cooling performance makes the higher
continuous output of the e-machine possible.
The inverter with silicon carbide technology for the EVSys800
electric drive has been fundamentally redesigned. Significant improvements
were achieved in each of the areas of electromagnetic
compatibility, power modules and capacitors in terms of installation
space, weight and sustainability.
The first thermal management system developed by ZF increases the
range of the electric vehicle by up to a third in real winter conditions.
It not only tempers the drive train with electric motor, inverter, battery
and voltage conversion, but also the vehicle interior.
The first central thermal management system (TherMaS) developed
by ZF for electric vehicles is integrated into the EVbeat
concept vehicle. TherMaS uses a central unit and intelligent
software to control all thermal processes for the driveline and passenger
compartment. The new design significantly reduces space
requirements and weight compared to previous approaches for
cooling and heating e-cars. A propane-based 800-volt heat pump
also requires significantly less energy. Because it is compact and
simple in design, it can be easily integrated into vehicles.
The TherMaS concept has three designated circuits for the first
time: At the center is the very small refrigerant circuit. This is prefilled
and hermetically sealed and is therefore maintenance-free.
In addition, the concept has no interfaces to other vehicle areas
such as the interior. ZF uses the fluorine-free, natural refrigerant
propane. Although only half the previous refrigerant is used, the
cooling capacity increases by a factor of two compared with refrigerants
commonly used today. If required, the central refrigerant
circuit serves two separately controllable cooling circuits in which
frost-protected water flows as usual: The first is designed for the
comparatively high temperatures of the electric motor, while the
second regulates the temperature of the power and charging electronics.
The control software regulates the cooling capacity.
Lighter and more compact: A new, coaxial reduction gear transmits
the drive forces of the electric motor via two planetary gear sets.
They not only generate the desired final drive ratio, but also take
over the fully integrated differential function.
A new, coaxial reduction gearbox transmits the drive forces of
the electric motor via two planetary gear sets. They generate the
desired final drive ratio, also perform the fully integrated differential
function. Compared with conventional offset concepts, in
which the input and output shafts are not on the same axis, the
coaxial solution reduces weight and installation space requirements
without compromising on efficiency, noise and vibration. In
combination with the winding technology, the drive can be made
significantly shorter, allowing installation in almost any vehicle
installation space.
" With this system, we can perfectly meet the main requirements
of our customers, namely efficiency, performance and costs, "
said Scharrer. The first technologies of the new ZF driveline are
expected to be available on the market from 2026.
For more info, see www.zf.com.
www.MagneticsMag.com
September/October 2023 * Magnetics Business & Technology 23
http://www.zf.com http://www.MagneticsMag.com
Magnetics Business & Technology - September/October 2023

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